Starter Battery Drains on Overnights

[JR Larsen]

I have a 2007 Hunter 41DS equipped with Freedom Inverter/Charger, Xantrex Remote, Panda Genset, AC etc. Up until now, she has been virtually problem free. Recently, I find that the starter battery drains almost completely down when on overnight cruises, while the house batteries stay charged up. We leave just one light on in the cabin typically and the anchor light on outside. I've checked both the Xantrex Remote display and the Freedom directly for any error conditions. None. Why would suddenly it seem that the starter battery drains before the house batteries. All the breaker switch positions appear set for normal operations. The inverter and charging appear to be normal. I get voltage readings on both battery banks at the 12vdc switch panel. Any ideas before I start tearing the boat apart, or worse hire a marine electrician to do same. Thanks !

 

[KD3PC]

If it is only your starter battery that is draining, you may want to look there first. Look for the 1-2-both-off switch and trace it's cables back to make sure that it works as it should. If this is the original battery, you may have a bad cell or battery. Most larger boats are going to have at least a house bank and a start bank, but since you mentioned the panda...there may be 3 or more banks...house, genny start, main start, etc.

Really need more info to go forward.

A word of advice, you may want to map/trace out where everything goes, before calling an electrician, else your first 4 hours of labor is going to be him doing this for you. If you do it, you will then know the layout, where the fuses and such are and the like. If he does it, he will forget by the time he gets home and you will be out some major $$.

keep us posted.

dave

 

[Bill Roosa]

Bad battery

Occam's Razor; the most likely answer is usually the right one.
The start battery all of a sudden starts discharge over night/not hold a charge. Probably a bad cell.
How old is the battery?
Do you use the start battery for loads while overnighting?

My suspicion is that you are probably not using the start batt for overnight loads so it is not discharging it is dieing. No load and loss of charge is classic bad battery syndrome.

Check your 3-way switch for proper position. If the house bats are on line and the start is not then it has to be a bad battery.

Put the battery on charge and take all the caps off. After 15 minutes check to see if one cell is bubbling a lot more than the others. That would be the bad cell. Turn off the charger and take an hour coffee break. Use a volt meter and measure between the + terminal and the cell next to it. Just stick the volt meter in the electrolyte being careful not to touch the plates. Continue to test cells. One will show no voltage increase from the last one. That should also be the one that was bubbling a lot.

Other possibilities (very low probability BTW), diode bad in alternator, bad insulation on one of the wires, broken 3-way switch.

 

[JR Larsen]

Re: Bad battery

Occam's Razor; the most likely answer is usually the right one.
The start battery all of a sudden starts discharge over night/not hold a charge. Probably a bad cell.
How old is the battery?
Do you use the start battery for loads while overnighting?

My suspicion is that you are probably not using the start batt for overnight loads so it is not discharging it is dieing. No load and loss of charge is classic bad battery syndrome.

Check your 3-way switch for proper position. If the house bats are on line and the start is not then it has to be a bad battery.

Put the battery on charge and take all the caps off. After 15 minutes check to see if one cell is bubbling a lot more than the others. That would be the bad cell. Turn off the charger and take an hour coffee break. Use a volt meter and measure between the + terminal and the cell next to it. Just stick the volt meter in the electrolyte being careful not to touch the plates. Continue to test cells. One will show no voltage increase from the last one. That should also be the one that was bubbling a lot.

Other possibilities (very low probability BTW), diode bad in alternator, bad insulation on one of the wires, broken 3-way switch.

Bill and Dave,

Thanks for responding to my post so quickly. I forgot to mention, I have one starter and two house batteries, on separate busses. I swapped out the starter battery for another one I had checked out as 100% working order. Same symptoms. There are two battery switches, one for each bank with only on/off positions, not a three-way. Even when I turn the starter battery switch to the off position, it appears to be on-line, accepting a draw. The boat is just three seasons old, and I didn't seem to have this problem until last weekend. Any other thoughts all ! Thanks !

 

[flhunter]

battery draining

I had a similar problem a few years ago. Mine turned out to be the diode in the Alternator as Bill sugested.

Whenever i have a problem like yours, I set my multimeter up for DC amps and put in in series with one of the battery cables.

Then I just start to unplug things like the alternator..fuel pump.. radio.. whatever is on that circuit.

If you have something drawing your battery down, the meter will show xx Milliamps (i.e. .09 mA) . When you disconnect the problem item from the circuit, the meter will show 0 mA.